On Bentley tuning, Sizaire axles and Lambda Head Gaskets

First up Des has just added 1.9 litres to his 3 Litre Bentley all done very nicely by Up the Creek Workshop the car is now quite a weapon, however it was running a bit rich. Most of us would at this point start randomly stuffing around with different needles for the SUs, this is where Des’s engineering background makes this a bit more like science.

If you look at Des’s photo on the left you will see the laptop is connected to a camera looking into the inlet of the SU, to the right the 10.3 is my air/fuel gauge temporally lashed to the dash and the gauge above the red lamp is the tacho. The readings in the pic were just in neutral however the next day it was repeated on a long hill, so with some measured guestimation new needles were ordered and it’s now running around 13:1 throughout the rev range, so all those gadgets have at last come in useful.

The Sizaire Naudin has now been off the road for 18 months waiting for a new front axle to be cast after the old one was found to be cracked. Alas after receiving the new one (and a spare luckily) it was found to have a warped spring pedestal so back it goes, hopefully the spare can be used as I don’t fancy waiting another 18 months.

The Lambda has been up to UTCW for some fettling before its holiday to Europe, as with so many jobs the list started small with reset the rear springs, check the brakes and the front wheel bearings. The springs were reset but the rear hubs were shot as were the rear wheel bearings and seals but the brakes and the front wheel bearings were fine so sort of equalled out. But there was a niggling problem of running hot at speed and this would need the head removed. Now any Lambda owner will tell you if you do not have a blown head gasket leave it alone, removing the head usually exposes the sorry state of an aluminium block in its final stages of decay but I just had to know.

The picture on left shows my rather unique block which is not too bad for a Lambda although a bit of a shock was the size of the bores as they have been sleeved down to make good some previously dodgy machining making my car the smallest capacity Lambda in existence. On the bright side it shouldn’t break a crank as overstressed it isn’t.

Lastly, I’ve stymied some oil leaks on le Bébé but I am struggling with my bargain Zenith carburettor that has the engine idling at slightly less than flat out, the throttle butterfly is a bit of a square peg in a round hole so that may be the problem. Once the Lambda is on the boat I’ll get back to this one.